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<head><meta charset="utf-8"><title>I-prioritize #76507 #[link_section] is unsound on Harvard a… · t-compiler/wg-prioritization/alerts · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/index.html">t-compiler/wg-prioritization/alerts</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html">I-prioritize #76507 #[link_section] is unsound on Harvard a…</a></h3>

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<a name="210077275"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2376507%20%23%5Blink_section%5D%20is%20unsound%20on%20Harvard%20a%E2%80%A6/near/210077275" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html#210077275">(Sep 15 2020 at 00:01)</a>:</h4>
<p><span class="user-group-mention" data-user-group-id="3111">@WG-prioritization/alerts</span> issue <a href="https://github.com/rust-lang/rust/issues/76507">#76507</a> has been requested for prioritization.</p>
<h1><a href="https://forge.rust-lang.org/compiler/prioritization/procedure.html#assign-priority-to-unprioritized-issues-with-i-prioritize-label">Procedure</a></h1>
<ul>
<li>Priority?</li>
<li>Regression?</li>
<li>Notify people/groups?</li>
<li>Needs <code>I-nominated</code>?</li>
</ul>



<a name="210104877"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2376507%20%23%5Blink_section%5D%20is%20unsound%20on%20Harvard%20a%E2%80%A6/near/210104877" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> apiraino <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html#210104877">(Sep 15 2020 at 08:53)</a>:</h4>
<p>So, it looks like there is an undefined behaviour on AVR architecture (Tier 3) when linking in the same address space <code>code</code> and <code>data</code> segments. By quickly glancing at the linked issues and the linked thread on the users forum, my (admittedly limited) understanding is that this is not  something that be very easily "fixed", it's kind of how these architectures work. I think OP is just asking to put a sort of "safeguard". Happy to receive more insights on this issue.</p>
<p>In short, given there's also a list of linked issues around the same theme that seem not to be critical, I'd warrant a <code>P-medium</code> (if not <code>P-low</code>).</p>



<a name="210120873"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2376507%20%23%5Blink_section%5D%20is%20unsound%20on%20Harvard%20a%E2%80%A6/near/210120873" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html#210120873">(Sep 15 2020 at 12:20)</a>:</h4>
<blockquote>
<p>it's kind of how these architectures work</p>
</blockquote>
<p>The reason I tagged as I-unsound is because it lets you cause UB from safe rust. This is a property of the language, not of the architecture (it just happens to only occur on AVR). I'm ok with P-low based on the linked issues, but I would prefer to have it I-nominated I think so it has more eyes on it.</p>



<a name="210121754"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2376507%20%23%5Blink_section%5D%20is%20unsound%20on%20Harvard%20a%E2%80%A6/near/210121754" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html#210121754">(Sep 15 2020 at 12:28)</a>:</h4>
<p>This is an issue on <em>all</em> architectures fwiw, but it's been known for a long time that linkage-controlling attributes can cause problems like this</p>



<a name="210121843"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2376507%20%23%5Blink_section%5D%20is%20unsound%20on%20Harvard%20a%E2%80%A6/near/210121843" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html#210121843">(Sep 15 2020 at 12:29)</a>:</h4>
<p>speaking of which, it would be great if someone could review <a href="https://github.com/rust-lang/rust/pull/72209">https://github.com/rust-lang/rust/pull/72209</a>, it's been sitting alone for a month</p>



<a name="210123187"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2376507%20%23%5Blink_section%5D%20is%20unsound%20on%20Harvard%20a%E2%80%A6/near/210123187" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html#210123187">(Sep 15 2020 at 12:41)</a>:</h4>
<p>Lint additions need to be T-lang approved AFAIK</p>



<a name="210123444"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2376507%20%23%5Blink_section%5D%20is%20unsound%20on%20Harvard%20a%E2%80%A6/near/210123444" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html#210123444">(Sep 15 2020 at 12:44)</a>:</h4>
<p>seems a little odd, but I'll post in <a class="stream" data-stream-id="213817" href="/#narrow/stream/213817-t-lang">#t-lang</a></p>



<a name="210134058"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2376507%20%23%5Blink_section%5D%20is%20unsound%20on%20Harvard%20a%E2%80%A6/near/210134058" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> apiraino <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html#210134058">(Sep 15 2020 at 14:08)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232545">Joshua Nelson</span> <a href="#narrow/stream/245100-t-compiler.2Fwg-prioritization.2Falerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6/near/210120873">said</a>:</p>
<blockquote>
<p>I'm ok with P-low based on the linked issues, but I would prefer to have it I-nominated I think so it has more eyes on it.</p>
</blockquote>
<p>completely agree <span aria-label="thumbs up" class="emoji emoji-1f44d" role="img" title="thumbs up">:thumbs_up:</span> <br>
and thanks for correcting my (ignorant) take on the issue :-)</p>



<a name="210242903"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2376507%20%23%5Blink_section%5D%20is%20unsound%20on%20Harvard%20a%E2%80%A6/near/210242903" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> apiraino <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html#210242903">(Sep 16 2020 at 10:18)</a>:</h4>
<p>Assigning <code>P-low</code>, but feel free to adjust if needed</p>



<a name="210242971"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2376507%20%23%5Blink_section%5D%20is%20unsound%20on%20Harvard%20a%E2%80%A6/near/210242971" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2376507.20.23.5Blink_section.5D.20is.20unsound.20on.20Harvard.20a.E2.80.A6.html#210242971">(Sep 16 2020 at 10:19)</a>:</h4>
<p>Issue <a href="https://github.com/rust-lang/rust/issues/76507">#76507</a>'s prioritization request has been removed.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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